Extension ladder



Aug. 28, 1956 M. PEARL 2,760,706

EXTENSION LADDER Filed May 19, 1953 2 Shets-Sheet 1 IN VENTOR AORNEYS Aug. 28, 1955 PEARL 2,760,706 EXTENSION LADDER Filed May 19, 1953 2 SheetsSheet 2 3 5 IN VENTOR wfarzrin a rZ ATTORNEYS nxrnnsron mnnnn a Marvin Pearl, Scranton, Pa, assiguorito scrauton Aiui This invention relates -to-extensionladders. An object of this invention is-to provide an extension ladder formed of a-series-of slidably connected together ladder sections with means for locking the sections together in extended position.

Another object of this invention is to provide an extension ladder which is formed out of lightweight metal. such as aluminum, having channeled rails which are produced by the extrusion process, and each rail havinga main inwardly facing channel and a second outwardly directed channel which forms a guide for an adjacent rail.

A further object of this invention is to provide a metal extension ladder including an improved spring-pressed dog for releasably locking the ladder sections together.

A further object of this invention is to provide an improved foot for a ladder which is of anti-slip characteristic and may be used on a smooth, hard surface or a soft surface.

With the above and other objects in view, my invention consists in the arrangement, combination and details of construction disclosed in the drawings and specification, and then more particularly pointed out in the appended claims.

In the drawings:

Figure 1 is a detailed side elevation, partly broken away, of an extension ladder constructed according to an embodiment of this invention,

Figure 2 is a detailed front elevation of the ladder,

Figure 3 is a sectional view taken on the line 33 of either Figure 1 or Figure 2,

Figure 4 is a fragmentary sectional view taken on the line 4-4 of Figure 2,

Figure 5 is a fragmentary perspective view of one of the side rails.

Referring to the drawings, the numerals 10, 11 and 12 designate generally a series of ladder extensions which are slidably connected together and releasably locked, as will be hereinafter described, in extended or contracted position. The ladder sections are of like construction and each section is formed of opposite side rails generally indicated at 13.

The side rails 13 are formed of relatively wide channel members 14 having an outer wall 15 and opposite side walls 16 and 17. Tubular rungs 18 are secured between the rails 13, being securely disposed through the walls 15 and the outer ends of the rungs 18 are upset as indi cated at 19.

Each rail 13 also includes a relatively narrow guide channel 20 which is formed integral with the side wall 17 and the outer wall 21 of the guide channel 20 is substantially shorter in width than the wall 17 so that when the rails are disposed in assembled position the side wall 16 of one rail will be slidably disposed within the channel member 20 and the outer walls 15 of the main channel members will be disposed in substantial alignment, as shown in Figure 3.

The rails 13 are preferably formed of metal such as 2,760,706 Patented Aug. 28, 1956 aluminum or the like and are produced by the extrusion process.

Each side wall 16 is formed with an inwardly projecting bead 22 and with an arcuate or convex outer side 23; The bead 22 provides a slidable contacting point for the wall 16 for engagement with the-inner side of the guide wall 21. The bead 22 and the convex side 23 provide minimum contacting surfaces for the side wall 16 with respect to the channel 20 in order to reduce friction-cbetween the side wall 16 and the walls of the channel 20-when the ladder is extended or contracted.

The ladder section 12 is the upper ladder section and the upper rung 18 of this section has rotatably mounted thereon a pair of rollers 24. These rollers 24 are adapted .to contact with the wall which is engaged by the upper ladder section 1-2 so that the ladder may be readily extended or contracted without marring the outer surface of the building wall.

Each ladder section has mounted on the lower rung 18 thereof a pair of spring-pressed locking members generally indicated at 25. The locking members 25 comprise a bar 26 which rotatably engages at one end about the rung 18 and the bar 26 is formed with a hook 27 engageable with a selected rung 18 of the adjacent ladder section. The hook 27 is provided with a relatively long lower bill 28 which in the collapsing or contracting of the ladder sections is adapted to engage over the upper side of each rung as the ladder sections are moved endwise, one relative to the other.

A spring 29 is secured as at 30 to a rung 18 of one ladder section and is secured as at 31 to the locking member 25 This spring is olf center with respect to the locking member 25 and constantly urges this locking member 25 to swing upwardly to a released position.

The ladder section 10 is the lower ladder section and has mounted on each side rail 13 thereof a foot member generally indicated at 32. The foot member 32 is formed of upwardly extending side members 33 which are pivotally secured as at 34 to the channel member 14. The foot member 32 also includes a bottom plate 35 connected between the side members 33, and an anti-slip rubber cushion member 36 having suction cups 37 is secured by fastening means 38 to the bottom plate 35.

One end of the bottom plate 35 has extended therefrom teeth 39, and a toothed plate 40 is disposed in face abutting relation to the bottom plate 35 at one end thereof and overlies the teeth 39 so as to form relatively heavy anti-slip teeth which are adapted to bite into a surface which is engaged by the lower end of the ladder.

In the use of this ladder assembly, the ladder sections 10, 11 and 12 or as many other sections as may be desired, are slidably connected together with the outer wall 16 of one ladder section slidably engaging in the channel 20 of an adjacent ladder section. The ladder sections may be extended by pushing one section upwardly with respect to the other section and with the lower ladder section 10 having the anti-slip feed 32 resting on a supporting surface. The provision of the rollers 24 will permit the ladder sections to be readily extended by a person standing on one of the ladder sections and conversely the ladder sections may be collapsed in the same manner.

The ladder hereinbefore described is preferably constructed out of aluminum which is light in weight and will permit the use of a number of these sections being slidably coupled together without having a ladder which is cumbersome or heavy.

In the initial formation of this extension ladder, the sections may be formed alike so that in the final assembly certain sections may be made as top and bottom sections, and as many intermediate sections may be used as may be desired.

I do not mean to confine myself to the exact details of construction herein disclosed, but claim all variations being formed of an inwardly facing channel member and i an outwardly facing guide channel of relatively narrow width formed integral with one wall of said inwardly facing channel member, the opposite wall of said inwardly facing channel member having a concave outer surface terminating at its extremity in a bead and slidably engaging in the narrow guide channel of an adjacent section, the outer surfaces of said inwardly facingchannels of adjacent sections being substantially aligned.-

2. An extension ladder comprising a plurality of slidably connected together ladder sections of substantially identical width, each section being formed of parallel side rails and rungs fixed between said rails, each rail being formed of an inwardly facing channel member and an-outwardly-facingguide-channel of relatively narrow width formed integral with one wall of said inwardly facing channel member, the opposite wall of said inwardly facing channel member having a concave outer surface terminating at its extremity in a bead and slidably engaging in the narrow guide channel of an adjacent sect tion, the outer surfaces of the inwardly facing channels of adjacent sections being substantially aligned, and

spring-pressed locking members carn'edby each ladder section forloclting' said'" sections together in adjusted position.

R e firiin c esz the tile of patent 2,636,659 Salisbury Apr. 28, 1953 

